As with the distance methods, all of the above methods of estimating 
are based on the assumptions of the IAM, i.e. no homoplasy.
Slatkin (1995) has shown that the
measures of average sum of squares of the difference in allele size are
related to 
. From coalescent theory it can be shown that
is related to the average coalescence times, such that,
where 
is the average time to coalescence of any two randomly chosen
alleles from the entire population, and 
is the average time to
coalescence of any two randomly chosen alleles drawn from the same
subpopulation (Slatkin 1991). In two
populations with divergent alleles, the average time to a common
ancestor for any two alleles in a subpopulation is going to be less
than the average time to coalescence of any 2 alleles drawn from the
entire population. Based on this relationship,
Slatkin (1995) developed an estimation
of 
that would incorporate the mutational history contained
within the alleles under the SMM, 
.
Where 
and 
are the average sum of squares of the difference
in allele size within a subpopulation and the entire population as
describe above. Slatkin noted that the 
and that the 
. Thus,
